add 2d module: camera, frame animation, tweens

1 files changed, 56 insertions, 0 deletions

diff --git a/kon/kon2d.c b/kon/kon2d.c
index 8ce56d8..0b963ac 100644
--- a/kon/kon2d.c
+++ b/kon/kon2d.c
@@ -128,3 +128,59 @@ void kon_drawFrame(kon_framebuffer_t *fb, const kon_image *sheet, int frameWidth
 	kon_drawImageEx(fb, sheet, src, (float)x + (float)frameWidth * 0.5f, (float)y + (float)frameHeight * 0.5f,
 	    (float)frameWidth * 0.5f, (float)frameHeight * 0.5f, -1.0f, 1.0f, 0.0f, KON_FILTER_NEAREST);
 }
+
+/*** tweens ***/
+
+float kon_easeValue(kon_ease_t ease, float t)
+{
+	if (!(t > 0.0f)) return 0.0f;
+	if (t >= 1.0f) return 1.0f;
+	switch (ease) {
+	case KON_EASE_IN: return t * t * t;
+	case KON_EASE_OUT: return 1.0f - (1.0f - t) * (1.0f - t) * (1.0f - t);
+	case KON_EASE_INOUT: return t < 0.5f ? 4.0f * t * t * t : 1.0f - 4.0f * (1.0f - t) * (1.0f - t) * (1.0f - t);
+	case KON_EASE_LINEAR: break;
+	}
+	return t;
+}
+
+void kon_tweenSet(kon_tween_t *tween, float value)
+{
+	tween->from = tween->to = value;
+	tween->duration = tween->time = 0.0f;
+	tween->ease = KON_EASE_LINEAR;
+}
+
+void kon_tweenStart(kon_tween_t *tween, float from, float to, float seconds, kon_ease_t ease)
+{
+	tween->from = from;
+	tween->to = to;
+	tween->ease = ease;
+	tween->time = 0.0f;
+	tween->duration = seconds > 0.0f ? seconds : 0.0f;
+}
+
+void kon_tweenTo(kon_tween_t *tween, float to, float seconds, kon_ease_t ease)
+{
+	kon_tweenStart(tween, kon_tweenValue(tween), to, seconds, ease);
+}
+
+float kon_tweenStep(kon_tween_t *tween, float dt)
+{
+	if (dt > 0.0f && tween->time < tween->duration) {
+		tween->time += dt;
+		if (tween->time > tween->duration) tween->time = tween->duration;
+	}
+	return kon_tweenValue(tween);
+}
+
+float kon_tweenValue(const kon_tween_t *tween)
+{
+	if (!(tween->duration > 0.0f)) return tween->to;
+	return tween->from + (tween->to - tween->from) * kon_easeValue(tween->ease, tween->time / tween->duration);
+}
+
+int kon_tweenDone(const kon_tween_t *tween)
+{
+	return tween->time >= tween->duration;
+}